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Wang Y, Demir B, Mohammad H, Oren EE, Anantram MP. Computational study of the role of counterions and solvent dielectric in determining the conductance of B-DNA. Phys Rev E 2023; 107:044404. [PMID: 37198817 DOI: 10.1103/physreve.107.044404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 04/01/2023] [Indexed: 05/19/2023]
Abstract
DNA naturally exists in a solvent environment, comprising water and salt molecules such as sodium, potassium, magnesium, etc. Along with the sequence, the solvent conditions become a vital factor determining DNA structure and thus its conductance. Over the last two decades, researchers have measured DNA conductivity both in hydrated and almost dry (dehydrated) conditions. However, due to experimental limitations (the precise control of the environment), it is very difficult to analyze the conductance results in terms of individual contributions of the environment. Therefore, modeling studies can help us to gain a valuable understanding of various factors playing a role in charge transport phenomena. DNA naturally has negative charges located at the phosphate groups in the backbone, which provides both the connections between the base pairs and the structural support for the double helix. Positively charged ions such as the sodium ion (Na^{+}), one of the most commonly used counterions, balance the negative charges at the backbone. This modeling study investigates the role of counterions both with and without the solvent (water) environment in charge transport through double-stranded DNA. Our computational experiments show that in dry DNA, the presence of counterions affects electron transmission at the lowest unoccupied molecular orbital energies. However, in solution, the counterions have a negligible role in transmission. Using the polarizable continuum model calculations, we demonstrate that the transmission is significantly higher at both the highest occupied and lowest unoccupied molecular orbital energies in a water environment as opposed to in a dry one. Moreover, calculations also show that the energy levels of neighboring bases are more closely aligned to ease electron flow in the solution.
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Affiliation(s)
- Yiren Wang
- Deparment of Electrical and Computer Engineering, University of Washington, Seattle, Washington 98105, USA
| | - Busra Demir
- Bionanodesign Laboratory, Department of Biomedical Engineering, and Department of Materials Science & Nanotechnology Engineering, TOBB University of Economics and Technology, Ankara 06510, Turkey
| | - Hashem Mohammad
- Department of Electrical Engineering, Kuwait University, P.O. Box 5969, Safat 13060, Kuwait
| | - Ersin Emre Oren
- Bionanodesign Laboratory, Department of Biomedical Engineering, and Department of Materials Science & Nanotechnology Engineering, TOBB University of Economics and Technology, Ankara 06510, Turkey
| | - M P Anantram
- Deparment of Electrical and Computer Engineering, University of Washington, Seattle, Washington 98105, USA
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2
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Tassinari F, Jayarathna DR, Kantor-Uriel N, Davis KL, Varade V, Achim C, Naaman R. Chirality Dependent Charge Transfer Rate in Oligopeptides. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:e1706423. [PMID: 29611223 DOI: 10.1002/adma.201706423] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2017] [Revised: 02/19/2018] [Indexed: 05/21/2023]
Abstract
It is shown that "spontaneous magnetization" occurs when chiral oligopeptides are attached to ferrocene and are self-assembled on a gold substrate. As a result, the electron transfer, measured by electrochemistry, shows asymmetry in the reduction and oxidation rate constants; this asymmetry is reversed between the two enantiomers. The results can be explained by the chiral induced spin selectivity of the electron transfer. The measured magnetization shows high anisotropy and the "easy axis" of magnetization is along the molecular axis.
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Affiliation(s)
- Francesco Tassinari
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | | | - Nirit Kantor-Uriel
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Kathryn L Davis
- Department of Chemistry, Manchester University, North Manchester, IN, 46962, USA
| | - Vaibhav Varade
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Catalina Achim
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, 15213, USA
| | - Ron Naaman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
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3
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Beall E, Ulku S, Liu C, Wierzbinski E, Zhang Y, Bae Y, Zhang P, Achim C, Beratan DN, Waldeck DH. Effects of the Backbone and Chemical Linker on the Molecular Conductance of Nucleic Acid Duplexes. J Am Chem Soc 2017; 139:6726-6735. [PMID: 28434220 DOI: 10.1021/jacs.7b02260] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Scanning tunneling microscope break junction measurements are used to examine how the molecular conductance of nucleic acids depends on the composition of their backbone and the linker group to the electrodes. Molecular conductances of 10 base pair long homoduplexes of DNA, aeg-PNA, γ-PNA, and a heteroduplex of DNA/aeg-PNA with identical nucleobase sequence were measured. The molecular conductance was found to vary by 12 to 13 times with the change in backbone. Computational studies show that the molecular conductance differences between nucleic acids of different backbones correlate with differences in backbone structural flexibility. The molecular conductance was also measured for duplexes connected to the electrode through two different linkers, one directly to the backbone and one directly to the nucleobase stack. While the linker causes an order-of-magnitude increase in the overall conductance for a particular duplex, the differences in the electrical conductance with backbone composition are preserved. The highest molecular conductance value, 0.06G0, was measured for aeg-PNA duplexes with a base stack linker. These findings reveal an important new strategy for creating longer and more complex electroactive, nucleic acid assemblies.
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Affiliation(s)
- Edward Beall
- Chemistry Department, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Selma Ulku
- Chemistry Department, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Chaoren Liu
- Chemistry Department, Duke University , Durham, North Carolina 27708, United States
| | - Emil Wierzbinski
- Chemistry Department, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
| | - Yuqi Zhang
- Chemistry Department, Duke University , Durham, North Carolina 27708, United States
| | - Yookyung Bae
- Chemistry Department, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - Peng Zhang
- Chemistry Department, Duke University , Durham, North Carolina 27708, United States
| | - Catalina Achim
- Chemistry Department, Carnegie Mellon University , Pittsburgh, Pennsylvania 15213, United States
| | - David N Beratan
- Chemistry Department, Duke University , Durham, North Carolina 27708, United States
| | - David H Waldeck
- Chemistry Department, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
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4
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Yin X, Kong J, De Leon A, Li Y, Ma Z, Wierzbinski E, Achim C, Waldeck DH. Luminescence quenching by photoinduced charge transfer between metal complexes in peptide nucleic acids. J Phys Chem B 2014; 118:9037-45. [PMID: 24975518 DOI: 10.1021/jp5027042] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A new scaffold for studying photoinduced charge transfer has been constructed by connecting a [Ru(Bpy)3](2+) donor to a bis(8-hydroxyquinolinate)2 copper [CuQ2] acceptor through a peptide nucleic acid (PNA) bridge. The luminescence of the [Ru(Bpy)3](2+*) donor is quenched by electron transfer to the [CuQ2] acceptor. Photoluminescence studies of these donor-bridge-acceptor systems reveal a dependence of the charge transfer on the length and sequence of the PNA bridge and on the position of the donor and acceptor in the PNA. In cases where the [Ru(Bpy)3](2+) can access the π base stack at the terminus of the duplex, the luminescence decay is described well by a single exponential; but if the donor is sterically hindered from accessing the π base stack of the PNA duplex, a distribution of luminescence lifetimes for the donor [Ru(Bpy)3](2+*) is observed. Molecular dynamics simulations are used to explore the donor-PNA-acceptor structure and the resulting conformational distribution provides a possible explanation for the distribution of electron transfer rates.
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Affiliation(s)
- Xing Yin
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
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Yin X, Wierzbinski E, Lu H, Bezer S, de Leon AR, Davis KL, Achim C, Waldeck DH. A three-step kinetic model for electrochemical charge transfer in the hopping regime. J Phys Chem A 2014; 118:7579-89. [PMID: 24813905 DOI: 10.1021/jp502826e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Single-step nonadiabatic electron tunneling models are widely used to analyze electrochemical rates through self-assembled monolayer films (SAMs). For some systems, such as nucleic acids, long-range charge transfer can occur in a "hopping" regime that involves multiple charge transfer events and intermediate states. This report describes a three-step kinetic scheme to model charge transfer in this regime. Some of the features of the three-step model are probed experimentally by changing the chemical composition of the SAM. This work uses the three-step model and a temperature dependence of the charge transfer rate to extract the charge injection barrier for a SAM composed of a 10-mer peptide nucleic acid that operates in the hopping regime.
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Affiliation(s)
- Xing Yin
- Department of Chemistry, University of Pittsburgh , Pittsburgh, Pennsylvania 15260, United States
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6
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Wierzbinski E, Venkatramani R, Davis KL, Bezer S, Kong J, Xing Y, Borguet E, Achim C, Beratan DN, Waldeck DH. The single-molecule conductance and electrochemical electron-transfer rate are related by a power law. ACS NANO 2013; 7:5391-401. [PMID: 23692478 DOI: 10.1021/nn401321k] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This study examines quantitative correlations between molecular conductances and standard electrochemical rate constants for alkanes and peptide nucleic acid (PNA) oligomers as a function of the length, structure, and charge transport mechanism. The experimental data show a power-law relationship between conductances and charge transfer rates within a given class of molecules with the same bridge chemistry, and a lack of correlation when a more diverse group of molecules is compared, in contrast with some theoretical predictions. Surprisingly, the PNA duplexes exhibit the lowest charge-transfer rates and the highest molecular conductances. The nonlinear rate-conductance relationships for structures with the same bridging chemistries are attributed to differences in the charge-mediation characteristics of the molecular bridge, energy barrier shifts and electronic dephasing, in the two different experimental settings.
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Affiliation(s)
- Emil Wierzbinski
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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Joshi T, Patra M, Spiccia L, Gasser G. Di-heterometalation of thiol-functionalized peptide nucleic acids. ARTIFICIAL DNA, PNA & XNA 2013; 4:11-8. [PMID: 23422249 PMCID: PMC3654725 DOI: 10.4161/adna.24019] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 02/14/2013] [Accepted: 02/15/2013] [Indexed: 12/21/2022]
Abstract
As a proof-of-principle, two hetero-bimetallic PNA oligomers containing a ruthenium(II) polypyridyl and a cyclopentadienyl manganese tricarbonyl complex have been prepared by serial combination of solid-phase peptide coupling and in-solution thiol chemistry. Solid-phase N-terminus attachment of Ru(II)-polypyridyl carboxylic acid derivative, C1, onto the thiol-functionalized PNA backbone (H-a-a-g-t-c-t-g-c-linker-cys-NH 2) has been performed by standard peptide coupling method. As two parallel approaches, the strong affinity of thiols for maleimide and haloacetyl group has been exploited for subsequent post-SPPS addition of cymantrene-based organometallic cores, C2 and C3. Michael-like addition and thioether ligation of thiol functionalized PNA1 (H-gly-a-a-g-t-c-t-g-c-linker-cys-NH 2) and PNA2 (C1-a-a-g-t-c-t-g-c-linker-cys-NH 2) to cymantrene maleimide and chloroacetyl derivatives, C2 and C3, respectively, has been performed. The synthesized ruthenium(II)-cymantrenyl PNA oligomers have been characterized by mass spectrometry (ESI-MS) and IR spectroscopy. The distinct Mn-CO vibrational IR stretches, between 1,924-2,074 cm (-1) , have been used as markers to confirm the presence of cymantrenyl units in the PNA sequences and the purity of the HPLC-purified PNA thioethers assessed using LC-MS.
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Affiliation(s)
- Tanmaya Joshi
- Institute of Inorganic Chemistry; University of Zurich; Zurich, Switzerland
| | - Malay Patra
- Institute of Inorganic Chemistry; University of Zurich; Zurich, Switzerland
| | - Leone Spiccia
- ARC Centre of Excellence for Electromaterials Science and School of Chemistry; Monash University; Clayton, VIC Australia
| | - Gilles Gasser
- Institute of Inorganic Chemistry; University of Zurich; Zurich, Switzerland
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8
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Li W, Sepunaru L, Amdursky N, Cohen SR, Pecht I, Sheves M, Cahen D. Temperature and force dependence of nanoscale electron transport via the Cu protein azurin. ACS NANO 2012; 6:10816-10824. [PMID: 23136937 DOI: 10.1021/nn3041705] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Solid-state electron transport (ETp) via a monolayer of immobilized azurin (Az) was examined by conducting probe atomic force microscopy (CP-AFM), as a function of both temperature (248-373K) and applied tip force (6-15 nN). At low forces, ETp via holo-Az (with Cu(2+)) is temperature-independent, but thermally activated via the Cu-depleted form of Az, apo-Az. While this observation agrees with those of macroscopic-scale measurements, we find that for holo-Az the mechanism of ETp at high temperatures changes upon an increase in the force applied by the tip to the proteins; namely, above 310 K and forces >6 nN ETp becomes thermally activated. This is in contrast to apo-Az, where increasing applied force causes only small monotonic increases in currents due to decreased electrode separation. The distinct ETp temperature dependence of holo- and apo-Az is assigned to a difference in structural response to pressure between the two protein forms. An important implication of these CP-AFM results (of measurements over a significant temperature range) is that for reliable ETp measurements on flexible macromolecules, such as proteins, the pressure applied during the measurements should be controlled or at least monitored.
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Affiliation(s)
- Wenjie Li
- Department of Materials & Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
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Bag SS, Talukdar S, Matsumoto K, Kundu R. Triazolyl donor/acceptor chromophore decorated unnatural nucleosides and oligonucleotides with duplex stability comparable to that of a natural adenine/thymine pair. J Org Chem 2012; 78:278-91. [PMID: 23171090 DOI: 10.1021/jo302033f] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We report the design and synthesis of triazolyl donor/acceptor unnatural nucleosides via click chemistry and studies on the duplex stabilization of DNA containing two such new nucleosides. The observed duplex stabilization among the self-pair/heteropair has been found to be comparable to that of a natural A/T pair. Our observations on the comparable duplex stabilization has been explained on the basis of possible π-π stacking and/or charge transfer interactions between the pairing partners. The evidence of ground-state charge transfer complexation came from the UV-vis spectra and the static quenching of fluorescence in a heteropair. We have also exploited one of our unnatural DNAs in stabilizing abasic DNA.
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Affiliation(s)
- Subhendu Sekhar Bag
- Bio-organic Chemistry Laboratory, Department of Chemistry, Indian Institute of Technology, Guwahati-781039, India.
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Wierzbinski E, Yin X, Werling K, Waldeck DH. The Effect of Oxygen Heteroatoms on the Single Molecule Conductance of Saturated Chains. J Phys Chem B 2012; 117:4431-41. [DOI: 10.1021/jp307902v] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Emil Wierzbinski
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Xing Yin
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Keith Werling
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - David H. Waldeck
- Department
of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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